Portable computing devices, such as wireless telephones and personal digital assistants (PDAs), continually require increased data storage capacity and processing speed. For example, a wireless telephone may concurrently serve as a digital camera; multi-media file player, and portable game player. Concurrent with increasing functionality and performance requirements, available battery volume is decreasing, e.g., due to smaller portable devices and/or volume being occupied by other hardware.
One known conventional technique for reducing power is to configure the computing device as switchable to a low power or “local memory access mode” in which access can be constrained to local memory. In the local memory access mode, a processing core may be allowed to access only a set of lower power, local resources, e.g., a local memory tightly coupled to the processing core, instead of having access to all available memory and device resources.
Conventional techniques, however, switch to the local memory access mode in response to a specific “mode switch” command. Therefore, absent such a mode switch command, external memory and other device resources can remain powered up, regardless of being unused. In addition, while in the local memory access mode, a need to quickly access the powered down external memory or other device resource may arise. However, until an explicit mode switch command is received, an attempt to perform that access can cause page faults.